Fuel and lubricating oils stabilized with tri (hydroxyphenyl) compounds



United States Patent 3,154,492 FUEL AND LUBRICATING OILS STABILIZED WITH TRIMYDRGXYPHENYL) COWOUNDS Hugh Wilma Bouiton Reed, Norton-on-Tees, England,

assignor to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain No Drawing. Filed .Iuly 14, 1.961, Ser. No. 124,020 Claims priority, application Great Britain, July 25, 1960, 25,784/60 Claims. (Cl. 252-52) This invention relates to fuel and lubricating oils.

In general, fuel and lubricating oils are susceptible to deterioration by oxidation, particularly at elevated temperatures. I have found that this deterioration may be inhibited by the presence of a minor amount of an additive comprising a tris(hydroxyary1) propane compound in which the hydroXyaryl groups are attached directly by their ortho or para positions to the chain CCHCH, two of the said hydroxyaryl groups being attached to the said chain by the terminal carbon atom which is shown with a hydrogen atom attached thereto.

It will be understood that the ortho and para positions are relative to the hydroxyl radicals of the hydroXyaryl groups.

The chain is preferably part of an alkyl chain which may be branched.

The hydroxyaryl groups are preferably like monohydroxyphenyl groups, particularly alkyl substituted monohydroxyphenyl groups in which at least one ortho position is occupied by an alkyl radical.

The additives of the present invention may be regarded as the non-resinous condensation products of an aldehyde molecule having an alpha-beta double bond and an unsubstituted alpha carbon atom, with three hydroxyaryl molecules each having a free ortho or para position relative to a hydroxy group in which the three molecules are attached by one or other of these positions as described, to the chain CCH-CH provided by the aldehyde molecule, the carbonyl carbon atom of which appears in this chain as the terminal atom shown with a hydrogen atom. The additives may be prepared by condensations of this kind.

These additives are preferably prepared from acrolein, crotonaldehyde or cinnamaldehyde. The chain in these cases is thus part of a propyl, n-butyl, or propylphenyl group. The additives are further preferably derived from phenols having alkyl substituents in the 3 and 6 positions relative to the hydroxy group in position 1, for example, 3,6-dimethylphenol, 3-methyl-6-ethylphenol, 3-methyl-6-tert.bntylphenol and 3-methyl-6 (alpha, alpha, gamma, gamma tetramethylbuyl) phenol, the hydroxyaryl groups in these examples thus being 1-hydroXy-3,6-dimethylphenyl,

l-hydroxy-S-methyl-6-ethylpheny1,

l-hydroxy-3-methyl-6-tert.butylphenol, or

1-hydroxy-3-methyl-6(alpha, alpha, gamma, gamma tetramethylbutyl) phenol.

The additives are effective in amounts of at most 5% by weight, and are preferably present in amounts between about 0.1% and about 2% by weight. They may be incorporated in any type of fuel or lubricant oil which is susceptible to deterioration by oxidation, for example kerosene and other liquid jet engine fuels, and lubricating oils based on natural or synthetic hydrocarbons and esters.

EXAMPLE Tris (para 3 methyl 6 tert.butylphenol)butane, prepared by condensing crotonaldehyde with. 3-methyl-6- tert.butylphenol, was dispersed in diiferent concentrations in samples of a commercial hydrocarbon turbine oil of viscosity 190 centistokes at C. The samples were then tested according to Test 114/ 56T, as published in Standard Methods for Testing Petroleum and Its Products (1961 edition) by The Institute of Petroleum. In the test, air was bubbled at the rate of 2 litres per hour for 90 hours through each sample maintained at C. in an open 200 ml. reactor tube, and the acid value of the oil then determined.

The results are given in the table following, together with the result from the same test applied to a sample of the oil with no additive.

Table Oil: Turbine oil base, viscosity centistokes at 100 F. Additive: Methyl trist(para-3-methyl-6-tert.butylphenol)- propane Wt. percent additive in sample: Acid value Nil 0.99

The results in the table show that a significant improvement in the stability of the oil tested is obtained with as little as 0.1% by weight, and that even greater stability is obtained with about 0.3% by weight upward.

I claim:

1. A stabilized composition of matter consisting essentially of an oil selected from the group consisting of lubricating oil and a normally liquid hydrocarbon fuel oil and a stabilizing amount of an additive of the formula:

wherein R is selected from the group consisting of hy drogen, lower alkyl and phenyl; X is 3,6-lower alkyl substituted l-hydroxyphenyl attached to the C atom in a position other than meta with respect to the hydroxy substituent; and Y is selected from the group consisting of hydrogen and X, one Y being hydrogen and the other Y being the same as X.

2. A composition according to claim 1 wherein said additive is tris(para-3-methyl-6-tert.butylphenol)butane.

3. A composition according to claim 1 in which the said oil is a turbine lubricating oil.

4. A composition according to claim 1 in which the proportion of the said additive is between about 0.1% and about 2% by weight.

5. A composition according to claim 4 in which the said proportion is about 0.3% to about 0.5% by weight.

References Cited by the Examiner UNITED STATES PATENTS 2,831,897 4/58 Harris et a1 252404 XR 2,862,976 12/58 Dubbs et al. 252-404 XR 2,885,385 5/59 Farnham 2-606l9 XR 3,026,264 3/62 Rocklin et al. 252-52 DANIEL E. WYMAN, Primary Examiner.

JULIUS GREENWALD, Examiner. 

1. A STABILIZED COMPOSITION OF MATTER CONSISTING ESSENTIALLY OF AN OIL SELECTED FROM THE GROUP CONSISTING OF LUBRICATING OIL AND A NORMALLY LIQUID HYDROCARBON FUEL OIL AND A STABILIZING AMOUNT OF AN ADDITIVE OF THE FORMULA: 